Recently, a digital camera and a digital video camera are provided with an interface, which is used for attaching an external storage device such as a memory card, in order to make up for shortage of capacity of an internal storage device (built-in memory) and in order to take out data of taken images and easily move the image data to other equipment. Likewise, in a portable telephone, a portable music player, a portable game machine, and the like, it has become more common to adopt a constitution allowing attachment of an external storage device.
Meanwhile, as the equipment that can use the above external storage device increases and realizes high functionality, the storage device is improved, so that the capacity is increased, and the functions are enhanced. For example, there has been known a storage device which is provided with a wireless communication module and can be directly connected to a communication network through wireless communication.
Since a storage device such as a memory card is used by being connected to various equipment, the storage device is required to have such a high versatility that the storage device can be used in the same way even though the storage device is connected to any equipment. It is preferable that functions newly added to the storage device with the realization of high functionality can be used regardless of combination of equipment.